JPH0783240A - Joint structure of frp(fiber reinforced plastic) shaft and joint, and joining method - Google Patents

Abstract

PURPOSE:To provide the joint structure of an FRP(fiber reinforced plastic) shaft and a joint and the joining method of them which is high in concentricity and straightness and retains high adhesive strength. CONSTITUTION:This joint structure is concerned with a joint structure and a joining method wherein a joint section which is tight in engagement, and is composed of a plurality of projected ribs 18 extended in the axial direction, is formed in the outer circumferential surface of the joint section 17 of a flange joint 12, and both the outer circumferential surface of the joint section 17 and the end section inner circumferential surface of a shaft 11 made of FRP(fiber reinforced plastic) are coated with adhesives, and the joint 12 is then inserted into the end section of the shaft 11 so as to be bonded and fixed therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to FRP (Fiber r
The joint structure between the shaft made of einforced plastic (fiber reinforced plastic) and the joint, in particular, the joint of the hollow FRP shaft is fitted by fitting the joint and fixed by an adhesive. The present invention relates to a joining structure and a joining method.

[0002]

FRP is a material excellent in specific strength and specific rigidity. However, FRP alone is rarely used as a structural material, and FRPs are joined together or with different materials,
Often used as a structural member. For example, when FRP is applied to the drive shaft, a shaft made of FRP and a metal flange joint for transmitting torque to this shaft are used by being joined.

When a flange joint made of metal is joined to a hollow shaft made of FRP, the weight saving effect of the shaft made of FRP has the advantages that the number of dangerous rotations is increased and vibrations and shakes accompanying rotation are reduced. It will be.

When the conventional steel shaft and the metal joint are joined, they are joined by welding. If the joining by the welding method is used, the shaft and the joint are joined with high dimensional accuracy, and the joining strength is increased. However, the welding method cannot be used for joining the FRP shaft and the joint made of different materials. And FRP
Regarding the joining of the manufactured shaft and the joint of dissimilar materials, at present, a joining method with high dimensional accuracy and high joining strength has not been established.

Regarding the connection between the FRP shaft and the joint made of different materials, for example, as disclosed in Japanese Patent Publication No. 4-2423, a ring-shaped tight fitting portion is formed on the end face of the cylindrical insertion portion of the metal joint. Equipped with, or JP-A-64-
As disclosed in Japanese Patent No. 49719, there has been proposed one in which a joint element having an outer diameter larger than the inner diameter of an FRP pipe is press-fitted and joined by frictional force. Further, as disclosed in JP-A-4-94921, the surface roughness of the outer peripheral surface of the joint portion of the joint element before press-fitting and the inner diameter of the joint portion of the shaft before press-fitting and the joint portion of the joint element. It has been proposed that the ratio of the outer diameters is set to a predetermined value.

When the FRP shaft 1 and the joint 2 are bonded and fixed by an adhesive, as shown in FIGS. 7 and 8, the fitting portion 4 provided so as to protrude from the flange 3 of the joint 2 is used. Is inserted into the FRP shaft 1, and an adhesive 5 is interposed between the fitting portion 4 and the FRP shaft 1 so as to fix them. In this case, in order to obtain the required strength, the gap between the FRP shaft 1 and the joint 2 is made larger so that the required adhesive 5 is filled in the gap between the two. A loose fit is used.

Alternatively, as shown in FIGS. 9 and 10, a circumferential groove 6 extending in the circumferential direction is formed on the outer peripheral surface of the fitting portion 4 of the joint 2, whereby the circumferential groove of the fitting portion 4 is formed. The portion where 6 is not formed is tightly fitted, and the joint 2 is joined to the FRP shaft 1 by the adhesive 5 filled in the circumferential groove 6.

[0008]

The joining structures shown in FIGS. 7 and 8 show the case where the fitting portion 4 of the flange joint 2 is a straight cylindrical joint 2, and the adhesive 5 is used. In order to fill the space between the fitting portion 4 and the inner peripheral surface of the shaft 1, the gap of the fitting portion 4 is made large.
However, according to this structure, when the adhesive 5 is heated to cure it, the viscosity of the adhesive 5 is lowered and the adhesive 5 easily flows, and as a result, the cores of the shaft 1 and the joint 2 are displaced from each other. Will be glued together. Further, when the adhesive 5 flows out, the shaft 1 and the joint 2 are misaligned, and the strength of the joint portion is also reduced.

As shown in FIGS. 9 and 10, when the clearance between the fitting portion 4 and the shaft 1 is made small in the portion other than the circumferential groove 6, the coaxiality between the FRP shaft 1 and the joint 2 and Straightness will be improved. However, when the joint 2 is inserted into the FRP shaft 1 and fitted therein, the adhesive applied to the inner peripheral surface of the FRP shaft 1 and the outer peripheral surface of the fitting portion 4 of the joint 2 is scraped off. ,
As a result, the amount of adhesive remaining in the gap between the joints is reduced. As a result, the adhesive does not reach the entire gap uniformly and sufficiently, and there is a drawback that the joint strength between the fitting portion 4 and the inner peripheral surface of the shaft 1 becomes insufficient.

That is, as shown in FIGS. 9 and 10,
By providing a tight fitting portion at the tip and the root side of the fitting portion 4 of the joint 2, accurate centering is possible, but in this case as well, the joint 2 is attached to the inner peripheral surface of the FRP shaft 1. At the time of fitting, there is a problem that the adhesive applied to the inner peripheral surface of the shaft 1 and the outer peripheral surface of the fitting portion 4 is scraped off, particularly at the tight fitting portion on the tip end side.

Therefore, in a structure in which an FRP shaft and a joint are joined together by using an adhesive, it is a serious problem to maintain high coaxiality and straightness between the shaft and the joint and to increase the strength of the joint.

The present invention has been made in view of the above problems, and has a joint strength capable of transmitting a large torque, and an FRP shaft excellent in coaxiality and straightness of the shaft. It is an object of the present invention to provide a joining structure and a joining method of a joint and a joint.

[0013]

According to the present invention, in a joint structure of a FRP shaft and a joint, a plurality of axial directions are provided on an outer peripheral surface of a joint fitting portion fitted to an inner peripheral surface of the FRP shaft. A tight fitting portion composed of an extended ridge is provided, and the two are joined by an adhesive interposed between the inner peripheral surface of the FRP shaft and the fitting portion of the joint. The present invention relates to a joint structure between an FRP shaft and a joint that are fixed to each other. Further, according to the present invention, as described above, a tight fitting portion formed by a plurality of protrusions extending in the axial direction is inserted into the inner peripheral surface of the end portion of the shaft without rotating the joint provided in the fitting portion. The present invention relates to a method for joining an FRP shaft and a joint.

In the present invention, the FRP shaft is composed of reinforcing fibers and matrix resin. Depending on the purpose of use of the shaft, its bending rigidity and torsional rigidity are high, and it is necessary to have a required torsional strength. Therefore, the reinforcing fiber is preferably a fiber having a high tensile strength and a high tensile elastic modulus, and is used in one kind or a combination of two or more kinds selected from carbon fiber, glass fiber, aramid fiber, boron fiber, ceramic fiber and the like. . Particularly preferred is carbon fiber which is excellent in specific strength and specific rigidity and has a large effect of reducing weight.

As the matrix resin reinforced by such reinforcing fibers, thermosetting resins such as epoxy resin, bismaleimide resin, unsaturated polyester resin, phenol resin and vinyl ester resin, ABS resin, polycarbonate resin, polyester. Resin, polyamide resin (nylon 6, nylon 6.6, nylon 6
Thermoplastic resins such as 10, nylon 6/11 and nylon 6/12) can be used. Epoxy resin and unsaturated polyester resin which are excellent in handleability are preferably used.

The FRP shaft is manufactured by a conventionally known method. Considering productivity and production cost,
A filament winding method or a sheet winding method may be used.

On the other hand, the joint is made of metal, synthetic resin, F
It may be made of RP or the like, and is appropriately selected according to the purpose of use, transmission torque, size, etc. of the FRP shaft.

A plurality of tightly fitting joints, each of which is formed by a protrusion provided on the fitting portion of the joint, are provided. Preferably 3
~ 16 pieces. If the number of ridges is less than three, the shaft and the joint cannot be fixed sufficiently, and the coaxiality between the shaft and the joint cannot be obtained with high accuracy. If the number of ridges exceeds 16, there is a drawback in that the bonding area decreases, the joint strength becomes insufficient, and at the same time the weight increases.

The width of the tightly fitting joint formed by the protrusions is
Although it is appropriately adjusted depending on the number of joints, it is preferably within the range of 2 to 20% of the circumferential length of the whole joint. Two
If it is less than%, the shaft and the joint cannot be fixed sufficiently, and the coaxiality between the shaft and the joint cannot be obtained with high accuracy. If the above-mentioned ratio exceeds 20%, the adhesive area is reduced, so that the adhesive strength is lowered.

It is preferable that the joint formed by the protrusions is provided on the outer peripheral surface of the joint fitting portion over the entire length in the axial direction, but the joint between the shaft and the joint is fixed for the purpose of reducing the weight and the like. The length can be shortened as long as it does not damage. However, also in this case, in consideration of the accuracy of the fixation of the shaft and the joint and the coaxiality, it is preferable to provide the ridge having a length of 70% or more of the total length of the fitting portion in the axial direction.

Further, the projections of the joint portion of the joint do not necessarily have to be provided in a straight line. For example, as shown in FIG.
The tip side and the root side of the fitting portion may be separated and provided alternately. When the ridges are staggered in this way, the fracture starts from the joint where the fitting is tight, and the fracture progresses in the axial direction. Since it is stopped, there is an advantage that destruction does not proceed at once.

In order to fit the joint to the inner peripheral surface of the end portion of the FRP shaft, the both should not be rotated in the circumferential direction,
It is preferable to insert the fitting slowly with it straightened to the shaft. Since the mating part of the joint is formed with a ridge extending in the axial direction, if the joint is rotated during insertion, the joint prevents the inflow of the adhesive and scrapes the applied adhesive. In addition, good adhesion cannot be achieved.

Although the fitting portion of the flange joint in the embodiment of the present invention is solid as shown in FIGS. 1 to 6, a hollow joint may be used according to the purpose.

The adhesive used in the present invention is preferably a liquid type. The viscosity considers lubricity when inserting the joint into the shaft, workability, and viscosity when curing,
It is preferable to use one having a range of 100 to 1000 poise at room temperature. Examples of the adhesive include Araldite (manufactured by Ciba-Geigy), Sony Bond (manufactured by Sony Chemical Co., Ltd.), and Three Roy (manufactured by Three Bond).

According to the joining structure of the present invention, the fitting portion of the joint is provided with a tight fitting portion having a plurality of protrusions extending in the axial direction intermittently along the circumferential direction.
The shaft can be positioned and fixed to the joint at the joint portion formed by these ridges, so that mutual coaxiality and high straightness between the shaft and the joint can be obtained.

Further, since there are a plurality of tightly fitted joints on the circumference, the conventional problem of scraping off the adhesive is eliminated. That is, the adhesive is allowed to flow evenly between the outer peripheral side of the fitting portion of the joint and the inner peripheral surface of the shaft through the groove between the ridges that form the joint portion of the joint. And can be firmly adhered, and have high adhesive strength.

The FRP shaft in the present invention is, for example, a drive shaft, an axle, a winding shaft, or the like.

[0028]

Example 1 A high-strength carbon fiber bundle (7 μm × 12000, Vesphite (registered trademark) manufactured by Toho Rayon Co., Ltd.) impregnated with 35% by weight of a bisphenol epoxy resin was prepared by a filament winding method using a mandrel. 90 ° / + 4 above
Laminate with a configuration of 5 ° / −45 ° / 20 °. After this, it is heat-cured to have an inner diameter of 60 mm and an outer diameter of 70 mm.
And the CFRP (Car
bonus fiber forced plast
A hollow shaft made of ic carbon fiber reinforced plastic) was obtained. This shaft is designated by the reference numeral 11 in FIGS.

A joint 12 having a construction to be inserted into the inner peripheral surfaces of both ends of the CFRP shaft 11 was prepared. Joint 1
2 is a fitting portion 1 so that it projects from the center of the flange 16.
Equipped with 7. Moreover, the fitting portion 17 is provided with four ridges 18 which extend in the axial direction and which form a tightly fitting joint portion along the circumferential direction on the outer peripheral surface thereof. The adhesive can be introduced from the groove 21 between the protrusions 18.

Here, the width of each of the ridges 18 in the circumferential direction is 2% of the total length of the circumference, and the ratio of the joint portion composed of four ridges on the circumference is 8%. . Further, in the present embodiment, the length of the protrusions 18 that form the joint portion is 100 mm, which is the total length of the fitting portion 17 in the axial direction. In this way, the flange joint 12 was manufactured so that the outer diameter was 60 mm and the thickness of the adhesive was 0.1 mm.

Apart from the shaft 11, the inner diameter is 60 mm
Prepare a transparent plastic pipe, and apply the adhesive to the inner peripheral surface of the pipe and the outer peripheral surface of the fitting portion 17 of the flange joint 12, respectively, and then insert the fitting portion 17 into the inner peripheral surface of the transparent pipe. Then, the filling state of the adhesive was observed. As a result, it was confirmed that the entire circumferential groove 21 excluding the joint portion 18 was uniformly filled with the adhesive.

Therefore, the araldite AW136N and the hardener HY are respectively provided on the inner peripheral surface of the joint portion of the CFRP shaft 11 and the outer peripheral surface of the fitting portion 17 of the flange joint 12.
After directly applying an adhesive compounding 944 (manufactured by Ciba-Geigy) at a ratio of 10: 4, a CFRP shaft 1
Insert the fitting portion 17 of the flange joint 12 into the inner peripheral surface of 1,
Curing was carried out at 80 ° C. for 30 minutes.

In this way, the CFRP shaft 11 having the steel flange joints 12 joined to both ends of the CFRP shaft 11 was subjected to a torsion test, and as a result, the joint portions of both were 8
It was destroyed with a torque of 60 kgf · m.

Example 2 As shown in FIG. 4, joints composed of three ridges 18 were formed on the outer peripheral surface of the fitting portion 17 of the flange joint 12 at 120 ° intervals. The width of these ridges 18 in the circumferential direction is 5% of the circumference, and the proportion of the joint portion composed of three ridges in the circumferential direction is 15%. Also, this joint 18
As is clear from FIG. 5, the length of was set to 100 mm, which is the same length as the entire length of the fitting portion 17. In this way, the flange joint 12 was manufactured so that the outer diameter was 60 mm and the thickness of the adhesive was 0.1 mm.

On the outer peripheral surface of such a flange joint 12 and on the outer peripheral surface of the fitting portion 17, an adhesive having the same composition as in Example 1 is applied, and the same CFRP shaft 1 as in Example 1 is applied.
Adhesives were similarly applied to the inner peripheral surfaces of both ends of No. 1 and inserted, and cured at 80 ° C. for 30 minutes in the same manner as in Example 1.
As a result of the twist test of the CFRP shaft having the steel flanges 12 joined to both ends of the CFRP shaft 11 as shown in FIG.
It was destroyed with a torque of gf · m.

Example 3 CFR prepared by a method similar to that described in Example 1
The shaft 11 made of P and the flange joint 12 made of steel were joined. The flange joint 12 used here is shown in FIG.
As shown in FIG.
Are provided alternately on the tip side and the root side.

Here, four ridges forming the joint portion 18 are provided on the tip side, and four ridges 18 are provided on the root side at intermediate positions in the circumferential direction of these four ridges 18, and they are staggered. I tried to be. The width of the joint portion 18 in the circumferential direction was 2% of the circumference, and the proportion of the joint portion 18 on the circumference was 8%. The length of the joint 18 is
Both the tip side and the root side were set to 50 mm, and the total of both was set to be equal to 100 mm, which is the total length of the fitting portion 17.

The CFRP shaft 11 thus obtained was subjected to the same torsion test as in Example 1 above, and as a result, 890 kg.
Both joints were broken by the torque of f · m.

Comparative Example 1 Example 1 was performed using the conventional joining structure shown in FIGS. 7 and 8.
Using a CFRP shaft 1 obtained in the same manner as above, a joint 2 having a smooth fitting portion 4 and a smooth fitting portion 4 having no recess for resin to flow in was inserted into the shaft 1 and joined.

The fitting dimensions of the CFRP shaft 1 and the flange joint 2, the type of the adhesive, the curing conditions, etc. were the same as in Example 1 above. The obtained CFRP shaft 1 was subjected to a torsion test, but it could not be subjected to a strength test because the coaxiality between the shaft 1 and the joint 2 was insufficient and the straightness was not sufficiently obtained. It was

Comparative Example 2 As shown in FIGS. 9 and 10, a circumferential groove 6 is formed in the middle portion of the fitting portion 4 of the flange joint 2 in the longitudinal direction, and the outer peripheral surface of the fitting portion 4 and the circumferential groove 6 are formed. The adhesive was applied to the inside, and the adhesive was applied to the inner peripheral surface of the shaft 1, and both were fitted and joined. The fitting dimensions of the CFRP shaft 1 and the flange joint 2, the type of adhesive, the curing conditions, etc. were the same as in Example 1.

According to such a method, since there is no recess for the adhesive to flow into the tight fitting portion formed on the entire circumference in the circumferential direction on the distal end side of the fitting portion 4, there is no adhesive. A part of the agent was scraped off. The CFRP shaft 1 thus obtained was subjected to the same torsion test as in Example 1, and as a result, 56
The joint was broken at a torque of 0 kgf · m.

[0043]

As described above, according to the present invention, the fitting joint of the joint fitted to the inner peripheral surface of the end portion of the FRP shaft is provided with a tight fitting portion composed of a plurality of axially extending projections. Thus, the fitting portion and the inner peripheral surface of the FRP shaft are joined and fixed with an adhesive.

Therefore, in particular, by the tight fitting portion formed by the protrusion provided in the fitting portion of the joint, relative coaxiality and straightness between the FRP shaft and the joint are realized with high accuracy. It becomes possible to do. Moreover, the adhesive can be evenly flowed in from the groove between the protrusions, so that the joint can be evenly and firmly adhered and fixed to the inner peripheral surface of the FRP shaft. In particular, since the ridges are formed in the axial direction on the outer peripheral surface of the fitting portion, by inserting the joint on the inner peripheral surface of the shaft end without rotating the shaft relative to the shaft, the adhesive can flow in more evenly. It becomes possible to realize strong adhesive fixation.

Therefore, according to the present invention, the dimensional accuracy is excellent,
Moreover, it becomes possible to join while maintaining high adhesive strength, and to obtain a joining structure between the FRP shaft and the joint, which is very advantageous for use at high speed rotation or for adhesive joining at a place where high torque is transmitted. Become.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a joining structure according to a first embodiment.

FIG. 2 is a front view of a joint.

FIG. 3 is a vertical cross-sectional view showing a joint structure.

FIG. 4 is a front view of the joint of the second embodiment.

FIG. 5 is a vertical sectional view showing a joint structure.

FIG. 6 is an exploded perspective view showing a joint structure according to a third embodiment.

FIG. 7 is an exploded perspective view showing a conventional joining structure.

FIG. 8 is a vertical cross-sectional view showing a joint structure.

FIG. 9 is an exploded perspective view showing another conventional joining structure.

FIG. 10 is a vertical cross-sectional view showing a joint structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 FRP shaft 2 Joint 3 Flange 4 Fitting part 5 Adhesive 6 Circumferential groove 11 FRP shaft 12 Joint 13 Through hole 16 Flange 17 Fitting part 18 Joint part (protrusion) 21 Groove 25 Adhesive

Claims (6)

[Claims] 1. In a joint structure of a FRP shaft and a joint, wherein a joint is fitted and attached to an inner peripheral surface of an end of a hollow FRP shaft, and the joint is fitted with a plurality of joint fitting portions. A joint structure between an FRP shaft and a joint, characterized in that a tight fitting portion composed of a protrusion extending in the axial direction is provided. 2. A ridge for forming a tightly fitting joint is 3
The joining structure between the FRP shaft and the joint according to claim 1, wherein the joint structure is provided with 16 to 16. 3. The method according to claim 1 or 2, wherein the total width of the protrusions constituting the tightly fitted joint in the circumferential direction is within the range of 2 to 20% of the total length of the circumference. FRP described
A joint structure between a shaft made of steel and a joint. 4. A ridge forming a tightly fitting joint,
The joining structure of the FRP shaft and the joint according to claim 1, wherein the fitting part is provided alternately on the tip side and the root side of the fitting part. 5. The joint structure of a FRP shaft and a joint according to claim 1, wherein the joint is made of any one of metal, synthetic resin, and FRP. 6. A method for joining a FRP shaft and a joint, wherein a joint is fitted and attached to an inner peripheral surface of an end of a hollow FRP shaft, and the joint is fitted with a plurality of joint fitting parts. An FRP shaft and a joint, characterized in that a tight fitting portion formed of a ridge extending in the axial direction is provided, and the fitting portion of the joint is inserted into the inner peripheral surface of the shaft end without rotating the joint. Junction structure.